Send a 1000 word essay via PM to the all the staff (note that each essay needs to be different for each staff member) In that essay explain why we should allow back in the section and if we reach a consensus you might regain the ability to post there again.
Jokes aside. Only an admin can issue a section ban and thus undo it. If you were banned it means you behaved poorly. You're going to have to wait a while and then message an admin to see if they will undo the ban.